fix(download): set Referer for AnimeFire CDN (lightspeedst.net)

lightspeedst.net, the CDN used by AnimeFire, returns 401 Unauthorized on
token-signed requests when the Referer header is absent. The batch download
path called downloadDirectHTTP without ever setting the global referer for
AnimeFire sources, since the AnimeFire scraper does not call SetGlobalReferer.

Guard: only set the referer when none is already active so other sources
are not affected.

Fixes: "The Angel Next Door Spoils Me Rotten" (and any AnimeFire anime)
failing to download with HTTP 401 Unauthorized in batch mode.

Author: Vittuu

internal/player/download.go

@@ -377,6 +377,11 @@ type directDownloadFunc func(string, string, *model) error
 type fallbackResolveFunc func(string, string) (string, error)
 
 func downloadAnimeFireDirectWithFallback(videoAPIURL, videoURL, path string, m *model) error {
+	// lightspeedst.net (AnimeFire CDN) requires Referer: https://animefire.io to authorise
+	// token-signed requests. Ensure it is set before the download client sends any request.
+	if util.GetGlobalReferer() == "" {
+		util.SetGlobalReferer("https://animefire.io")
+	}
 	return runAnimeFireDirectDownloadWithFallback(
 		videoAPIURL,
 		videoURL,